460272domain: NAppears in sequencesa(1) = 1; for n>1, a(n) = smallest number which is not a sum or product or power of any subset of the numbers a(1) to a(n-1).at n=22A126326a(0) = 1; a(n) = 3 * Sum_{k=0..floor((n-1)/2)} binomial(n-1,2*k) * a(n-2*k-1).at n=9A352280